A 248-gram piece of aluminum initially at 94.1°C is dropped into water in a coffee-cup calorimeter initially at 2.2°C.  If the final temperature of the aluminum and water is 18.7°C, what mass (in g) of water is present in the calorimeter? Assume all heat transfer occurs between the aluminum and water, and that the density of water over the relevant temperature range is 0.997 g/mL.  Show all work, and highlight your answer in a readable background color.

To a beaker containing water, you add so much table sugar that it doesn’t fully dissolve in the water.  Which of the following is true about the contents of the beaker?

New element X has two isotopes.  Isotope 1 has an isotopic mass of 311.001363 amu, whereas isotope 2 has an isotopic mass of 314.983097 amu.  If the atomic mass of X is 314.293201 amu, calculate the relative abundance of isotope 2. Show all work, and highlight your final answer in a readable background color.

(1) To open the equation editor, click the icon that says “Insert Math Equation” (looks like a square root symbol). Editor opens in Basic View by default. (2) Pressing left parenthesis will automatically put in the right parenthesis after that, and you’ll be able to type anything inside the parentheses. (3) The “Basic” menu has the functions for subscripts, superscripts, fractions, and normal math operations (4) The “Greek” menu allows you to put in Greek letters. If you want to type something in isotopic notation, you will need the Advanced View.  Click the link that says, “Switch to Advanced View”. (5) You will have to type what you want in a special code, using symbols to indicate superscript and subscript.  Don’t use spaces. ^ for superscript _ (underscore) for subscript use squiggly brackets { } after the ^ and _ symbols if multiple characters are to be superscripted or subscripted. after inserting the equation, you can resize by clicking on the equation, and dragging on one of the corners to make the equation smaller or larger Example:  ^{cats}_{dogs}eat^{food!}                     results in            

Which of the following has the greatest number of neutrons?

4.04 g of nitrogen combines with 11.46 g of oxygen to produce a compound with a molar mass of 108.0 g/mol. (5 pts)  What is the empirical formula of the compound? (3 pts)  What is the molecular formula of the compound? Show all work, and highlight final answers in a readable background color.  Make sure to label your answers as “empirical formula” or “molecular formula”.

What is the symbol of the element below?  Enter the name using correct case (lowercase/uppercase). calcium

What is the symbol of the element below?  Enter the name using correct case (lowercase/uppercase). magnesium

A new element, greenriverium (Gr), has three naturally-occurring isotopes.  Isotope 1 has a mass of 56.8901 amu, isotope 2 has a mass of 59.0074 amu, and isotope 3 has a mass of 60.0253 amu.  The percent abundance of isotope 1 is 36.1331%, and the percent abundance of isotope 2 is 51.9012%.  What is the atomic mass of Gr, in amu? Must show work for full credit.  Put your final calculated answer in a readable background color.

(1) To open the equation editor, click the icon that says “Insert Math Equation” (looks like a square root symbol). Editor opens in Basic View by default. (2) Pressing left parenthesis will automatically put in the right parenthesis after that, and you’ll be able to type anything inside the parentheses. (3) The “Basic” menu has the functions for subscripts, superscripts, fractions, and normal math operations (4) The “Greek” menu allows you to put in Greek letters. If you want to type something in isotopic notation, you will need the Advanced View.  Click the link that says, “Switch to Advanced View”. (5) You will have to type what you want in a special code, using symbols to indicate superscript and subscript.  Don’t use spaces. ^ for superscript _ (underscore) for subscript use squiggly brackets { } after the ^ and _ symbols if multiple characters are to be superscripted or subscripted. after inserting the equation, you can resize by clicking on the equation, and dragging on one of the corners to make the equation smaller or larger Example:  ^{cats}_{dogs}eat^{food!}                     results in